/*
* drivers/irqchip/irq-crossbar.c
*
* Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
* Author: Sricharan R <r.sricharan@ti.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/err.h>
#include <linux/io.h>
#include <linux/irqchip.h>
#include <linux/irqdomain.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/slab.h>
#define IRQ_FREE -1
#define IRQ_RESERVED -2
#define IRQ_SKIP -3
#define GIC_IRQ_START 32
/**
* struct crossbar_device - crossbar device description
* @lock: spinlock serializing access to @irq_map
* @int_max: maximum number of supported interrupts
* @safe_map: safe default value to initialize the crossbar
* @max_crossbar_sources: Maximum number of crossbar sources
* @irq_map: array of interrupts to crossbar number mapping
* @crossbar_base: crossbar base address
* @register_offsets: offsets for each irq number
* @write: register write function pointer
*/
struct crossbar_device {
raw_spinlock_t lock;
uint int_max;
uint safe_map;
uint max_crossbar_sources;
uint *irq_map;
void __iomem *crossbar_base;
int *register_offsets;
void (*write)(int, int);
};
static struct crossbar_device *cb;
static void crossbar_writel(int irq_no, int cb_no)
{
writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
}
static void crossbar_writew(int irq_no, int cb_no)
{
writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
}
static void crossbar_writeb(int irq_no, int cb_no)
{
writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
}
static struct irq_chip crossbar_chip = {
.name = "CBAR",
.irq_eoi = irq_chip_eoi_parent,
.irq_mask = irq_chip_mask_parent,
.irq_unmask = irq_chip_unmask_parent,
.irq_retrigger = irq_chip_retrigger_hierarchy,
.irq_set_type = irq_chip_set_type_parent,
.flags = IRQCHIP_MASK_ON_SUSPEND |
IRQCHIP_SKIP_SET_WAKE,
#ifdef [31mCONFIG_SMP[0m
.irq_set_affinity = irq_chip_set_affinity_parent,
#endif
};
static int allocate_gic_irq(struct irq_domain *domain, unsigned virq,
irq_hw_number_t hwirq)
{
struct irq_fwspec fwspec;
int i;
int err;
if (!irq_domain_get_of_node(domain->parent))
return -EINVAL;
raw_spin_lock(&cb->lock);
for (i = cb->int_max - 1; i >= 0; i--) {
if (cb->irq_map[i] == IRQ_FREE) {
cb->irq_map[i] = hwirq;
break;
}
}
raw_spin_unlock(&cb->lock);
if (i < 0)
return -ENODEV;
fwspec.fwnode = domain->parent->fwnode;
fwspec.param_count = 3;
fwspec.param[0] = 0; /* SPI */
fwspec.param[1] = i;
fwspec.param[2] = IRQ_TYPE_LEVEL_HIGH;
err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
if (err)
cb->irq_map[i] = IRQ_FREE;
else
cb->write(i, hwirq);
return err;
}
static int crossbar_domain_alloc(struct irq_domain *d, unsigned int virq,
unsigned int nr_irqs, void *data)
{
struct irq_fwspec *fwspec = data;
irq_hw_number_t hwirq;
int i;
if (fwspec->param_count != 3)
return -EINVAL; /* Not GIC compliant */
if (fwspec->param[0] != 0)
return -EINVAL; /* No PPI should point to this domain */
hwirq = fwspec->param[1];
if ((hwirq + nr_irqs) > cb->max_crossbar_sources)
return -EINVAL; /* Can't deal with this */
for (i = 0; i < nr_irqs; i++) {
int err = allocate_gic_irq(d, virq + i, hwirq + i);
if (err)
return err;
irq_domain_set_hwirq_and_chip(d, virq + i, hwirq + i,
&crossbar_chip, NULL);
}
return 0;
}
/**
* crossbar_domain_free - unmap/free a crossbar<->irq connection
* @domain: domain of irq to unmap
* @virq: virq number
* @nr_irqs: number of irqs to free
*
* We do not maintain a use count of total number of map/unmap
* calls for a particular irq to find out if a irq can be really
* unmapped. This is because unmap is called during irq_dispose_mapping(irq),
* after which irq is anyways unusable. So an explicit map has to be called
* after that.
*/
static void crossbar_domain_free(struct irq_domain *domain, unsigned int virq,
unsigned int nr_irqs)
{
int i;
raw_spin_lock(&cb->lock);
for (i = 0; i < nr_irqs; i++) {
struct irq_data *d = irq_domain_get_irq_data(domain, virq + i);
irq_domain_reset_irq_data(d);
cb->irq_map[d->hwirq] = IRQ_FREE;
cb->write(d->hwirq, cb->safe_map);
}
raw_spin_unlock(&cb->lock);
}
static int crossbar_domain_translate(struct irq_domain *d,
struct irq_fwspec *fwspec,
unsigned long *hwirq,
unsigned int *type)
{
if (is_of_node(fwspec->fwnode)) {
if (fwspec->param_count != 3)
return -EINVAL;
/* No PPI should point to this domain */
if (fwspec->param[0] != 0)
return -EINVAL;
*hwirq = fwspec->param[1];
*type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
return 0;
}
return -EINVAL;
}
static const struct irq_domain_ops crossbar_domain_ops = {
.alloc = crossbar_domain_alloc,
.free = crossbar_domain_free,
.translate = crossbar_domain_translate,
};
static int __init crossbar_of_init(struct device_node *node)
{
int i, size, max = 0, reserved = 0, entry;
const __be32 *irqsr;
int ret = -ENOMEM;
cb = kzalloc(sizeof(*cb), GFP_KERNEL);
if (!cb)
return ret;
cb->crossbar_base = of_iomap(node, 0);
if (!cb->crossbar_base)
goto err_cb;
of_property_read_u32(node, "ti,max-crossbar-sources",
&cb->max_crossbar_sources);
if (!cb->max_crossbar_sources) {
pr_err("missing 'ti,max-crossbar-sources' property\n");
ret = -EINVAL;
goto err_base;
}
of_property_read_u32(node, "ti,max-irqs", &max);
if (!max) {
pr_err("missing 'ti,max-irqs' property\n");
ret = -EINVAL;
goto err_base;
}
cb->irq_map = kcalloc(max, sizeof(int), GFP_KERNEL);
if (!cb->irq_map)
goto err_base;
cb->int_max = max;
for (i = 0; i < max; i++)
cb->irq_map[i] = IRQ_FREE;
/* Get and mark reserved irqs */
irqsr = of_get_property(node, "ti,irqs-reserved", &size);
if (irqsr) {
size /= sizeof(__be32);
for (i = 0; i < size; i++) {
of_property_read_u32_index(node,
"ti,irqs-reserved",
i, &entry);
if (entry >= max) {
pr_err("Invalid reserved entry\n");
ret = -EINVAL;
goto err_irq_map;
}
cb->irq_map[entry] = IRQ_RESERVED;
}
}
/* Skip irqs hardwired to bypass the crossbar */
irqsr = of_get_property(node, "ti,irqs-skip", &size);
if (irqsr) {
size /= sizeof(__be32);
for (i = 0; i < size; i++) {
of_property_read_u32_index(node,
"ti,irqs-skip",
i, &entry);
if (entry >= max) {
pr_err("Invalid skip entry\n");
ret = -EINVAL;
goto err_irq_map;
}
cb->irq_map[entry] = IRQ_SKIP;
}
}
cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
if (!cb->register_offsets)
goto err_irq_map;
of_property_read_u32(node, "ti,reg-size", &size);
switch (size) {
case 1:
cb->write = crossbar_writeb;
break;
case 2:
cb->write = crossbar_writew;
break;
case 4:
cb->write = crossbar_writel;
break;
default:
pr_err("Invalid reg-size property\n");
ret = -EINVAL;
goto err_reg_offset;
break;
}
/*
* Register offsets are not linear because of the
* reserved irqs. so find and store the offsets once.
*/
for (i = 0; i < max; i++) {
if (cb->irq_map[i] == IRQ_RESERVED)
continue;
cb->register_offsets[i] = reserved;
reserved += size;
}
of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map);
/* Initialize the crossbar with safe map to start with */
for (i = 0; i < max; i++) {
if (cb->irq_map[i] == IRQ_RESERVED ||
cb->irq_map[i] == IRQ_SKIP)
continue;
cb->write(i, cb->safe_map);
}
raw_spin_lock_init(&cb->lock);
return 0;
err_reg_offset:
kfree(cb->register_offsets);
err_irq_map:
kfree(cb->irq_map);
err_base:
iounmap(cb->crossbar_base);
err_cb:
kfree(cb);
cb = NULL;
return ret;
}
static int __init irqcrossbar_init(struct device_node *node,
struct device_node *parent)
{
struct irq_domain *parent_domain, *domain;
int err;
if (!parent) {
pr_err("%s: no parent, giving up\n", node->full_name);
return -ENODEV;
}
parent_domain = irq_find_host(parent);
if (!parent_domain) {
pr_err("%s: unable to obtain parent domain\n", node->full_name);
return -ENXIO;
}
err = crossbar_of_init(node);
if (err)
return err;
domain = irq_domain_add_hierarchy(parent_domain, 0,
cb->max_crossbar_sources,
node, &crossbar_domain_ops,
NULL);
if (!domain) {
pr_err("%s: failed to allocated domain\n", node->full_name);
return -ENOMEM;
}
return 0;
}
IRQCHIP_DECLARE(ti_irqcrossbar, "ti,irq-crossbar", irqcrossbar_init);